Automatic steering for ships



3111151411938- -F. s; HODGMAN 2,120,950 I AUTOMATICSTEERING FOR-SHIPS v original Filed April- 1:5, 1955 2 sheets-sheet 1 1 vENToR June'14, 1938. F, s. HODGMAN -A Y 2,120,950

AUTOMATIC STEERING Fon SHIPS Original Filed April 13. 1935 2 Shees-Sl'xeet. 2

Y Patented Jan-14,1938

`PATENT yoI-fi'i'tvzft:

STEERING FOR SHIPS Frederick AS. Hodgman, Glen Rock, N. J., assignor vto Sperry Gyroscope Company, 1nc.,.ABrooklyn,n N. YI., a corporation of New York Application April 13, 1935, Serial No. 16,173 Renewed October 20, 1937 13 Claims. (Cl. 114-144) This invention relates to automatic steering devices for ships orother dirigible craft. In o rder to maintain-a high speed ship on its course, many factors enter in addition to the relative position of the compass Vand ships heading at any particular instant, such as the necessity for preventing the ship, due to its momentum, from swinging beyond its prescribed course as it' is brought back to the course. According to the present invention, I propose a rudder control from a gyro compass or other base line, which is responsive not only to the relative position of the ship and compass, but also to the relative or apparent velocity of turn of the ship and compass. In order to eect this purpose, I have devised a novel mechanism for moving a member a distance proportional tothe apparent velocity Y of turning of the compass, and which is therefore indicative of the rate of turn of the ship. I

2o am aware that on paper, at least, it has been proposed to employ a rate of turn indicating devvice in automatic steering devices, but all such' Y prior devices have involved, insofar as I am aware, an auxiliary gyroscope ofthe turn indicator type for obtaining the rate. Such devices, however, add extra complications and are impractical on shipboard on account of the fact that rolling and pitching seriously aiect the accuracy and per'- formance of this type of gyroscope. Referring to the drawings showing lseveral forms my invention may assume.'

Fig. l is a diagrammatic view and partial wir-` ing diagram of my invention.

Fig. 2 is a detail of the rate differentiating dey vice. Fig. 3 is a development of the cam slot em ployed in the mechanism for actuating a course transmitter.v j Fig. 4 .is a wiring diagram ofthe limit switches and control motor for the rudder.

Y Fig. 5 is a detail showing-a modied form of.

rate diierentiating mechanism.

Fig. 6 is a top view of a ships steering stand in which a small auxiliary follow-up in otor'is used between the compass actuated controller and the main controller which operates the rudder motor. 4In the drawings the compass actuated 55` controllerjl is shown as one or more concentric ce shown` in my prio `Patent No. 1,965,378, dated July 3, 1934,

rings on which a trolley or trolleys 2, on a rotatable arm, bear. In this. instance the trolley arm is shown as turned from a repeater-motor 3 actuated from a master compass i. The rings are' substantially semicircular and the twohalves 5 insulated from each other. The rings are mount- 4 ed for rotation about the axis of rotation of the trolley arm and are rotated from a follow-back. connection from an auxiliary motor 5 which is actuated from the controller and which actuates '10 the main controller 33 and a follow-back con.

nectlon to auxiliary controller I. `4As shown, the motor 5 turns ashaft 6 through suitable gearing, which shaft in turn is connected to a shaft 'I through sprocket and chain gearing` 8. The.15 shaft 1, in turn, is shown'as actuating a gear 9, on which controller rings are mounted through pinion I0, idler Il, gear I2 and .variable lost motion device I3, the position of which may be adjusted by a cam I4. 'I'he gear'9 may-also 20 actuate an idler I5 and large gear I6, which turns a compass card I1. n

Course changes may be interposed by means of a course changing knob I3 which actuates,

through bevel gears I9 and 20, one arm of a 25v differential geartrain 2|. A shaft 22 is conA nected to the arm of the gear train opposite the shaft 1, and will therefore be actuated both from the follow-up from the motor 6 andthe course changing knob I3, but the card I1. being un- 30 affected by said knob, willshow true compass headings. An additional ships heading indicator .24 may be provided -above the card I1 and actuated from. the shaft n through any suitabler gearing," such as worm 25, worm,wheei 23 and 35 flexible shaft 21.

'I'he shaft 22 also turns. through an elongated pinion 28, a gear 29 on shaft 30. which turns at reduced speed a -worm wheel 3l through a worm 32. The gearing is such that the worm wheel 3I o makes onerevolution for one complete turnof the ship and is therefore synchronous with the compass and is used as the means for actuating a main controller 33. To this end there is shownl a cam 34 on the shaft o! said gear. which ispro- 45 vided with a slot 35, which is shown developed in' Fig. 3. This slot osclllates ,a self-synchronous transmitter 36 through an angle preferably some-v what less than for one revolution of the gear 3I through suitable linkage, such as a link 31l 50 having a pin at one end engaging said slot and connected at its opposite-end to apivoted lever 38 which reciprocates link .33 connected to an,

arm 40 on the shaft of the transmitter. Saidtransmitter actuates a self-synchronous repeater 4 55' vspectively, to said disks 53 and 54.

motor 4| at the after end of the ship, which turns the motor contacts 42 of the main controller 33.

For introducing the rate of turn factor, I employ a device also actuated from the compass which differentiates the turn of the ship with respect to time. As shown, the-shaft 6 also actuates, through any suitable form of gearing, a nut 43 threaded on a. shaft 44. Said gearing is shown as comprising a plurality of groups of bevel gears 45 and 46, the former having incorporated therein a reversing clutch 41 so that the nut may be rotated in either direction from the motor 5. The nut itself is mounted for rotation in a bearing 86 and has a gear 48 attached thereto, which is driven from a pinion 49 actuated, in turn', from friction disks 53 and 54, which are rotatably but nonslidably mounted on an extension of the threaded shaft 44. The shaft 44, in` turn, is connected to a planetary arm 55 of a differential gear train,` the other two arms of which are formed by bevel gears 56 and 51 connected, re-

Since the disks normally rest on the opposite sides of the center of rotation of the driving disk (see Figs. 1 and 2), it will be apparent that the center arm' will not rotate as long as said disks maintain this position. If, however, the nut 43 is rotated so as to advance or retract the screw shaft, the disks will be rotated'at unequal speeds, thereby rotating the center arm until the threaded shaft is screwed back again in its nut to re- Y store the position of equilibrium. The accuracy of the #1 followup is such that the motor will start and stop continuously from any movement of roller 2. A'I'he full speed of the servo-motor is selected to produce-rotation of rings slightly greater than the maximum rate at which roller `2 can turn in azimuth. For any given turning rate .of the ship, therefore, the rings will have a similar follow-up rate, which rate is also made up of a large number of starts and stops. The time lag of the speed gear system is such as to show a displacement which is proportionalA to this average speed. Therefore the threaded shaft will be positioned longitudinally a distance proportional to and indicative of the rate of turn of the ship. This factor may be introduced differentially into the position of the gear 3l. To this end the extension of shaft 44 is shown as connected through a .thrust bearing 58 to the shaft 3D so as topush the same axially when the shaft 44 is moved axially, thereby rotating the gear 3| through the axial movement of the worin 32. Under certain sea conditions it may be advisable to vary vvthe amount of rudder movement applied for a given rat of turn of the ship, and in order to effect this in a simple manner, I have shown a means for varying the speed of the motor 5| through a potentiometer 59 connected in the .armature circuit thereof. It will be clear that for any increase or decrease in the speed of Spinning motor 5|, there will be a lesser or a greater displacement of the speed gears and shaft 44, when compared to the normal rate of turn of ship may be made to turn through large angles with less rudder than hard over, which acts as provided withv a pair of oppositely threaded' worms 63 and 63' which revolve cams 64 and 64' in opposite directions. Normally these cams are arranged so that one will open the circuit of the main steering motor 65 when the rudder limit is reached in one direction, while the other opens the 'circuit forjthe other extreme position of the rudder, but it will readily be apparent that by changing the relative position of the cams with respect to the rest of the system, the rudder angle may be altered.- This may be conveniently accomplished by means of a maneuvering rudder knob 66 which turns a nut 61 threaded on a short shaft 68 so as to advance or retract such shaft, and with it move axially shaft 62, thereby v displacing the cams 54 and 64'; in the same direction. As will be apparent from Figs. 1 and 4, this has the eiect of altering the rudder throw in both directions at the same time, since the two cams are normally revolved in opposite directions by the rotation of the shaft 62,.

'I'he limit switch, as shown, is novel in the sense that it cooperates with controller 33 to provide a two part remote control of a distant object, such as the rudder. @It provides two-way remote control, whereby the rudder may be returned to lesser angles at will, as well as increased to greater angles.

Themaincontroller at the after end actuates the main reversible motor 65 directly, but I pre-- fer to also employ limit switches 10 and 1| at the` rudder, which remain fixed, the cams for operating the same, 12 and 13, being actuated directly from the motor shaft. A

'I'he motor is shown as turning the rudder R directly through Worm 14 and worm sector 15, but it will be understood that if desired, any suitable steering engine may be interposed. The follow- -back connection from the rudder to the main controller is represented as effected from sector` 15 on the rudder, which is shown as turning-the follow-up rings 33 of the controller through a gear (not shown).- y Referring now to the wiring diagram in Fig. 4, showing the main controller and motor circuits, Y the two ringsJB and 1 6' of the main ,controller are connected to contact arms 11 and 11', said arms having Arollers vthereon adapted to b e engagedA by the cams 64 and 64'. When disengaged, the circuit is completed through, each of wires 18 and 18' through the main limit switches 10 and 1l and through the oppositely wound field coils 65' of the motor 55, so that the motor will be driven in one direction or the other, depending upon whether the trolley 42 is on segment 16 or 16'. Assuming the motor to be running in a direction to rotate the cam 84' to the left, it will be seen that the circuit will be broken at switch 30 by the opening ofthe switch arm 11' if said cam strikes the arm before the switch 1| is opened, the cam then resting on inclined surface 90'.' If, however, the pilot then desires -to turn the rudder back part way, he turns knob '66 further, which will cause the roller to ride on top of cam u' and complete contact al; which will excite the opposite motor field through switch arm 11 and contact 30'.'

'nie grdiippr switches u, u and as are ctu- 75 ated from the auxiliary hard-over steering handle 86 (Fig. 6). When this handle is out, as shown in Fig. 6, the automatic steering gear is functioning and the switch 83 is closed to the position shown in Fig. 4. When, however, it is desired to steer by hand, the handle is pushed inwardly to bring notch 81 under the ball 88, thereby moving the switch 83 upwardly intothe dotted line position (Fig. 4). In this position the movementof the handle 86 to the right or left operates the switches 84 and 85 to steer the ship through the same electric steering motor 65 as employed when'steering the ship automatically.

A somewhat diiferent form of rate indicating device is shown in Fig. 5. According to this form, the disk 59 is rotated, as before, at con-g stant speed from a motor 5I. In this case the two .disks 53 and 54 are replaced by what is known as a two-ball integrator 82, whichis radially adjustableon the surface of saiddisk, so that it will be evident that the balls will be revolved at a rate proportional to the radial move'- ment thereof over the disk. The balls drive a` cylinder 83 on shaft 84 which, in turn, drives a.

planetary arm- 85 of a planetary gear train.

One arm of said train is shown as actuated di rectly from the auxiliary motor 5, while the third arm actuates, through suitable gearing, a nut 48' of Fig. 1, the same being threaded on a shaft 44 and held against axial movement in bearing 86. The axial movements of the shaft 44' move the two-ball integrator radially on the disk 50 so that the movements of the shaft 99', corresponding to shaft 39, indicate the rate of turn of the ship.

A further slight mcdicaton is shown in Figs.

'1, 8 and,9 in kconnection with the method of actuating the limit cams G4 and 64 on the bridge. According to this modification, the main controller 33' is placed at the control device in the pilot house instead of aft and a follow-back connection is provided between the rudder and the controller by means of transmitter 90 at the rudder and repeater motor 9|' which noty only drives the limit cams |84 and lllthrough shaft 62', but also provides a follow-up connection to the controller by turning the trolley 42.` The contact rings in this instance are shown as turned from the cam 34 by means of the rack bar 31,-the teeth of which mesh with the gear In this case the variation in the position of the limit cams is shown'as effected by mounting the contact arms |11' on gears 98 and 98', respectively,`which may be rotated with respect to the knob operates to turn said gears in opposite di- .cams by means'of the adjusting-knob 66'., Said rections through pinions 99 and 89. V

The advantages ,of some' of'the hereinbefore described novel features of my invention 'lie in the adaptability ofA my invention to steering a high speed ship under greatly diiferent condi jqtions. Whenprocee'ding at high speed in calm weather, it is desirable that the ship Ybe held on astraight course and that yawing be eliminated. -Under these conditions the rheostat 59 should be adjusted to give a vfairly large movement of the'shaft 44 for changes-of rate of turn so as to quickly apply a large rudder for'rapid rates tocheck the yaw. When proceeding more slowly or .in arough sea, the' motor 5I may be slowed down, or the rate device may be eliminated en tirely by moving" the clutch 41 to the mid position.

`tends to such use.

vtionsfrom `alsoimeasuringthe rate of deviationLmeans for actuating the rudder by said first two means It is also a well known fact that when a ship is rolling and pitching, a violent yawing effect takes place, known as a weather yaw, which is of fairly large amplitude and of much greater rate than the ordinary ships yawing. Therefore, under severe weather conditions I may nd it desirable to reverse the effect of the rate differentiating device in order to diminish rather than to increase the -rudder throw as the rate of yaw increases. This maybe conveniently accomplished by throwing the clutch 41 in the reverse position.

'Ihe pilot hou'se limit switches 64 and 64 are advantageous when a eet is maneuvering in signalled and set on the controller by knob I8.

In accordance with the provisions of the patent statutes, I have herein described the principle and operation of`my invention, together with the apparatus which' I now `consider to representthe best embodiment thereof, but I desire` to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by othermeans. Also, While it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined,- and the invention ex- Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In an automatic steering device for ships, a master compass, a controller actuated ltherefrom for actuating the ships rudder, said actuating means including'a device for differentiating the relative turning of the ship and compass with respect to time, and means for varying the time element oflsaid device for the purpose.

specied.

2. In an automatic steering device for dirigible craft, such as ships, a rate of turn determining device, a craft's heading maintaining device, means whereby the crafts rudder may be controlled from the latter device alone, and means whereby said'control devices may be combined either to lessen or increase the rudder throw at will for rapid yaws of the craft. l

3'. In an automatic steering device for a ship `91 on which the contact segments are mounted. 5 having a master C0mPaSS'C0mDaSS .Controlled means for detecting deviations from course, compass controlled means for* also measuring the rate of deviation,.both said means being controlled primarily from said master compass, and

means for actuating the rudder by said first two means. jointly.

'at a speed proportional to its radial distance from the center koi! -said disk, a threaded shaft and rotary` nut for adjusting radially said member, one of said shaft or nut being rotated by said member and the other by said compass means, and means for actuating the rudder from the radial position Vof said ,member and the course deviation detecting means.

5. In an automatic steering device for'ships, compass controlled means for detecting `devia-- course, compass controlledA means for jointly, and means for varying or reversing the effect of said rate means under diierent weather conditions.

- 6. An automatic steering device as claimed in claim 4,'in which means are provided for varying the speed of rotation of said disk at will, to vary the relativev eiiect of the rate means under different sea conditions.

'7. An automatic steering device as claimed in claim 4, in which means are provided for reversing the rotation of said disk to reduce rudder throw for weather yaw.

8. In an automatic steering device for ships, a master compass, a repeater motor actuated therefrom, a mechanical differentiating device for differentiating the turning of said motor with respect to time, and a controller actuating the ships rudder, operated diierentially from said device andrepeater motor.

9. In an. automatic steering device for ships, compass controlled means for detecting devia- Ations from course, compass controlled means for also measuring the rate of deviation, means for actuating the rudder by said rst two means jointly, and means for varying the effect of said l rate means under diierentweather conditions.

10. In an automatic steering device for ships, compass controlled means for detecting deviations from course, compass controlled means for also measuring the rate of deviation, means for actuating the rudder by said first two means,

and means for varying the manner in which said rst two means are combined to either increase or decrease the normal rudder angle under dif-v ferent sea conditions.

11. Inan automaticsteering device for ships, the combination with a master compass, a disk normally driven at uniform speed, a rotatable member driven by said disk at a speed proportional to its radial distance from the center of said disk, a threaded shaft and rotary nut for adjusting radially said member, one of said shaft /r nut being rotated by said member and the other by said compass means, and means for actuating the rudder from the radial position of said member.

12. An automatic steering device as claimed in claim 1l, in which means are provided for varying the speed of rotation of said disk at will, to

-vary the relative effect of the rate means under different sea conditions.

13. In an automatic steering device for dirigible craft, such as ships, a direction maintaining means, a controller actuated therefrom for turning the crafts rudder, said actuating means including a device for diflerentiating the relative turning of the craft and direction means with respect to time, and means for varying the time element of said device to vary the proportional correction introduced by said device with l 

